The specific aim of the research proposal presented herein is to study how lymphocytes derived from the thymus (T cells) respond per se to a variety of experimental maneuvers that have been shown to effect the immune response. We plan to assay the response of the T cells by measuring their DNA synthesis. We plan to obtain a relatively pure population of T cells by injecting thymocytes into lethally irradiated animals and at intervals thereafter harvesting the spleens. Using this technique we plan to test how T cells respond to a large variety of different antigens. With a limited number of antigens we then plan to obtain dose response curves. Once this is done we plan to test the effects of passive antibody, adjuvants, antigenic competition, macrophage processing of antigens, and reticulo-endothelial blockade on T cell activity. We also plan to study short-term memory, cell migration, cell recruitment, and the kinetics of tolerance induction. Lastly, we shall study hapten-carrier relations and the genetics of the response to artificial polymers.